It's reassuring to know that, after four years in London, I'm still learning new things.
For example, in New Zealand*, if a dog runs up to you and starts yapping away, jumping all around you and nipping at your heels and generally disregarding its place in the food chain, it's a perfectly acceptable deterrent to yell: "GET OUT OF IT YA MONGREL!" and clip it sharply on the ear. Kiwi* dog owners will regard you as well trained in the ways of doggie-discipline, having to fall back on it themselves quite frequently (indeed, is there any other way to get out of that situation that doesn't involve electric cattle prods?)
In London, on the other hand (as I just learned not twenty minutes ago), dog owners will react as though you'd just attacked their poor retarded child. I'm not sure if the words: "You Monster!" were actually uttered, but the tone of voice was such that I certainly remember them.
Well, they say that if you learn one new thing every day, you're doing well...
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* When I say 'New Zealand', I am of course referring to that zone of New Zealand that exists outside of Auckland. Aucklanders are just as pretentious as Londoners, if not moreso.
This is a 
But all you learned is what's going to happen the next time some yappy mongrel 'invades your aura', it's not going to change how you react, is it? The 'GET OUT OF IT YA MONGREL!' bit will still happen like, you'll just expect to be referred to as a monster, rather than it being a surprise.
No?
Yeah, well next time, rather than expecting to bask in the respect of a fellow doggie-discipline disciple, I'll be ready to go on the offensive and add: "...learn how to control your dumb-ass mutt in public, or next time I'll do more than clip his ear!"
I did exactly the same thing to this little kid once....
The best thing to do is to lean over and whisper: "I'm gonna fuckin' kill you." and then go back to your paper.